Payload transport systems vary greatly in size, payload capacity and complexity. Manually operated payload transport systems are generally designed to be easy to use, controllable and responsive. However, balancing these desires in a system that can convey the intended payloads in the particular environment is often challenging.
Take, for example, patient handling and transportation in healthcare environments. Manual handling of patients exposes care givers to dangerously high strains, especially in their lower backs, resulting in possible injuries. For this reason, patient handling equipment for the transfer of a patient from one location to another has been developed. These vary, for example, from wheeled beds and trolleys to mobile slings and hoists, mobility frames and similar devices. Equipment such as this is now used in the day to day work in a multitude of settings including hospitals, care homes and personal residences. Proper use of such equipment can significantly lower the risk for injury to the care giver and also of risk of slips, falls, strains and knocks to the patient.
However, the introduction of such equipment is not without its issues. It is well known for manual hospital beds and the like to be heavy, difficult to start moving or stop, difficult to direct and have “minds of their own”, despite the best efforts of its operator pushing in the desired direction. Additionally, equipment that may be useful in a hospital environment may not be suitable for use in a residential environment, for example, meaning that different equipment may be needed in different environments despite being used for the same or similar purpose.
Powered or power assisted propulsion systems have been developed, both in the form of systems built-in to the chassis of the equipment, for example a bed frame, stretcher, hoist or the like and as devices to be added to an existing chassis. While generally helpful, such systems often do not provide propulsion in all directions that the chassis can be moved in. As a result, the propulsion system must be deactivated if the chassis is to be moved in the direction that is not covered by the propulsion system (for example, sideways).
A number of power assisted propulsion systems have been introduced to address this issue. However, it is often the case that the operator (the care giver or other person driving the chassis) still needs to drive the chassis from a certain position due to the fixed position of the user interface for operating the power assisted propulsion system.